1. Field of the Invention
This invention pertains generally to thermostat control devices and more specifically to thermostat control devices of the type which employ time controlled heat emission to modify the temperature sensed by the thermostat.
2. Prior Art
The concept of utilizing heat emitted from a heating element to supplement the control of a thermostat is well known. For example, U.S. Pat. No. 2,969,916 discloses the use of resistance heating to effect premature operation of a thermostat in a heating or cooling system. U.S. Pat. Nos. 2,838,332, 3,784,094, 3,339,043, 2,628,034 and 1,809,293 are further exemplary of prior art temperature control systems which utilize this concept.
Due to the recent energy crisis and its accompanying increase in the cost of fuel there has been an increasing consumer demand for fuel saving devices. This invention relates to one such class of devices, namely those in which time controlled heat emission is employed to modify the operation of a thermostat control. Typically, such devices contemplate a resistor positioned near a thermostat, the flow of current to the resistor being controlled by a timer. When current flows through the resistor, the resistor emits heat with the result that the thermostat senses the higher "local" temperature caused by the resistor rather than the general room temperature actually present in the room. Consequently, the heating system delivers less heat to the room and fuel savings result. Of course, when no current is flowing through the resistor, the "local" temperature is the same as the general room temperature and the thermostat operates in the conventional fashion. Such devices are generally employed in connection with a thermostat regulated heating system and provide the capacity to activate or deactivate the heating system at some preselected time in the future. In modified form, these devices may also be employed in connection with thermostat regulated cooling systems.
In one such device, manufactured by the Fuel Sentry Corporation and marketed under the name Fuel Sentry, the resistive element is disposed in a housing which is fixedly secured to the wall beneath the thermostat. A cyclical timer is contained in a separate enclosure which is adapted to be plugged directly into a standard wall outlet. A wire connects the resistive element to the timer enclosure. The only means provided in this device for adjusting the quantum of heat radiated to the thermostat is a damper which may be interposed between the resistive element and the thermostat. Moreover, inasmuch as the timer is disposed in an enclosure which is plugged directly into the wall, the user must gain access to the wall outlet each time he wishes to reset the timer. This is particularly disadvantageous to the elderly and infirm since outlets are often located on the lower portions of the wall and access to them is frequently obscured by furniture.